I hope you just scrolled down a wee bit to that chat line, lol. When it comes to Miranda vs Jack, you should just for who you want to help (or enable) most. I always liked Jack more, so I went for her instead, and some info you can read from the Shadow Broker is pretty sad and interesting about both. Each has a degree of flaws and grow a lot as characters, so I think either would make good romances. I also didn't go for Miranda out of bro trust with Jacob, and she's not really my type, but that's just me. Do you because this is your story. Hell, try to romance both at the same time and see what happens. Just do you.

Unlike Tali or Liara, who admire you from the beginning, these 2 Ladies hide behind their biotic capabilities and their power, as they are quite alone and vulnerable.

Jack was tortured and therefore does not trust easily, as she has been used befor. She doesn't want personal feelings because it hurts when they are gone, except you show your are genuine and patient, she might show you her real self.

Miranda was tortured but had to fight for her free will and position and still has to which makes her look like a Diva. Both have in common that a friendship or more is dangerous as it can jeopardize the mission or endanger themself as both are on the run.

After their loyalty missions you have proven to them that you are honest, genuine and someone who will protect them and that can be trusted. This puts them both in conflict with themselfes in order to let their guard down for you.

Bith are unique as both show sides you would not have expect. You should make a different save file and try both of them especially if you want to continue the romance in ME3.

Btw at theor little dispute after the loyalty missions, be advised you loose both loyalty and romance option, if you side with one or the other. Though you can gain rhe loyalty back, a romance will be off limits. So better to persuade them via Blue/Red dialog.